SYNOPSIS

#include <systemd/sd-event.h>

int sd_event_run(sd_event *event, uint64_t usec);

int sd_event_loop(sd_event *event);

DESCRIPTION

sd_event_run()

may be used to run a single iteration of the event loop specified in the
event
parameter. The function waits until an event to process is available, and dispatches the registered handler for it. The
usec
parameter specifies the maximum time (in microseconds) to wait for an event. Use
(uint64_t) -1
to specify an infinite timeout.

sd_event_loop()
invokes
sd_event_run()
in a loop, thus implementing the actual event loop. The call returns as soon as exiting was requested using
sd_event_exit(3).

RETURN VALUE

On failure, these functions return a negative errno-style error code.
sd_event_run()
returns a positive, non-zero integer if an event source was dispatched, and zero when the specified timeout hit before an event source has seen any event, and hence no event source was dispatched.
sd_event_loop()
returns the exit code specified when invoking
sd_event_exit().

ERRORS

Returned errors may indicate the following problems:

-EINVAL

The
event
parameter is invalid or
NULL.

-EBUSY

The event loop object is not in the right state (see
sd_event_prepare(3)
for an explanation of possible states).

-ESTALE

The event loop is already terminated.

-ECHILD

The event loop has been created in a different process.

Other errors are possible, too.

NOTES

These APIs are implemented as a shared library, which can be compiled and linked to with the
libsystemdpkg-config(1)
file.